In recent years seats for cars and light trucks have been formed by molding a foam bun that will serve as the seat cushion, and then attaching a pre-stitched fabric cover to the foam bun. Often, the fabric cover is attached to the foam bun by insert molding touch fastener strips into the outer surface of the foam bun and attaching cooperating touch fastener strips to an inner surface of the fabric cover. Generally, the fastener strips are attached to the fabric cover along the seams where the cover is stitched together and held in place by the seam stitching. The touch fastener strips allow the seat manufacturer to rapidly and semi-permanently attach the fabric cover to the foam bun by pulling the fabric cover over the foam bun and pressing the opposed touch fastener strips on the foam bun and fabric cover together.
The touch fastener strips on the foam bun are typically recessed in trenches to allow the seams in the fabric cover to be indented below the surface of the seat cushion. Indenting the seams in this manner forms aesthetically appealing indented creases in the surface of the seat cushion upholstery for a tailored look.
Conventionally, the touch fastener is positioned in the mold such that the touch fastening surface is flush against a surface of the mold causing the touch fastening surface to be exposed in the finished foam product. Accordingly, when using such a molding process, care must be taken to avoid fouling of the touch fastening surface with the liquid foamable composition. For example, referring to FIG. 1A, a touch fastener 10 is placed in a mold cavity 114 with the fastener elements 20 positioned adjacent a depression 112 in a mold surface 110 for the positioning of the touch fastener 10. Referring to FIG. 1B, once the touch fastener 10 is correctly positioned into the depression 112 in the mold surface 110, a liquid foaming material 111, such as a two component system, is poured or injected into the mold cavity 114. The foaming material then solidifies, and the entire foam block is removed with the touch fasteners 10 adhered to its surface.
During this process, some liquid foaming material can leak around the edges of the base of the touch fastener into the space between the fastener elements (e.g., hooks), which are positioned inside the depression of the mold cavity. Leaking of the foaming material into the fastener elements can, in some cases, be reduced or prevented by providing a seal or gasket in between the touch fastener 10 and the portion of the mold surface 110 surrounding the depression 112.
Some attempts to prevent fouling include attaching a temporary, removable tape or film over the touch fastening surface during the molding process, and disposing a seal around the peripheral margin of the fastener elements. See for example, U.S. Pat. Nos. 4,842,916 and 5,766,723.